Recently, demand for photographing still images and moving images via photographing apparatuses have increased. In addition, demand for photographing apparatuses with high pixel density and high optical magnification have increased. Accordingly, a weight of a lens in a photographing apparatus and a weight of a structure having a lens mounted thereon have increased.
A step motor may be used to move a lens in a photographing apparatus along an optical axis. However, when the step motor is used, securing a large rotational force may not be easy due to the actuation of the step motor. Thus, when the step motor is used, a reduction structure, which includes a gear train, is used to increase the rotational force by reducing the high number of revolutions of the step motor. The gear train includes a plurality of gears engaged with each other.
However, vibration and noise may occur in such a reduction structure due to the impact between gears and deformations of the gear teeth due to a twisting moment generated along a rotational axis of each gear. In addition, the vibration and noise may increase when the lens driving source is driven at high speed, and such vibrations and noise may result in a loss of the driving force and cause mechanical defects accompanied by generation of filings and heat.
Such vibration, noise, and subsequent mechanical defects may directly affect the performance of the photographing apparatus. Especially, these factors may be more critical when photographing moving images with the photographing apparatus.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.